1. Technical Field
Embodiments of the present disclosure generally relate to an electronic device, and more particularly to a semiconductor memory device.
2. Related Art
Semiconductor memory device may be classified into volatile memory devices and nonvolatile memory devices.
Although the nonvolatile memory device has a relatively low write and read speed, it maintains stored data even without any external power source. The nonvolatile memory device is typically used for long-term persistent storage. Examples of the nonvolatile memory device include a Read Only Memory (ROM), a Mask ROM (MROM), a Programmable ROM (PROM), an Electrically Programmable ROM (EPROM), an Electrically Erasable and Programmable ROM (EEPROM), a flash memory, a Phase-change RAM (PRAM), a Magnetic RAM (MRAM), a Resistive RAM (RRAM), a Ferroelectric RAM (FRAM), and the like. The flash memory may be divided into a NOR type and a NAND type.
Like random-access memories (RAM), the flash memory may be freely programmed and erased, and, like the ROM, the data stored in the flash memory can be maintained even in the absence of a power supply. The flash memory is widely used as a storage medium of a portable electronic device, such as a digital camera, a Personal Digital Assistant (PDA), and an MP3 player.